Police use of GPS tracking in investigations is something of a hotbed issue that calls into question how much privacy people are entitled to. But when it's used successfully, as it was to arrest a California man who committed identity theft against 300,000 people, that argument becomes much more complex.

According to Cnet's Declan McCullagh, a Los Angeles man by the name of Richard Delgado who obtained a whole lot of JC Penney credit card numbers, and then went on a shopping spree. Then one victim who had been hit brought it to the attention of a U.S. Postal Inspector, who found Delgado's number through Facebook and linked it to calls he made to the credit card bank.

Williams, the postal inspector, obtained a warrant from a federal judge to track Delgado's phone to shopping malls in southern California where fraudulent transactions took place. (Whether police are required to obtain a warrant or not for GPS tracking is still constitutionally unsettled terrain — the U.S. Supreme Court will hear a case this fall that is likely to set the ground rules for this kind of surveillance.)

It's hard to argue against something when it's used to do good, but if GPS tracking becomes protected by the law, what happens if it starts being used in a corrupt manner? [Cnet]